Tamm-horsfall protein regulates granulopoiesis and systemic neutrophil homeostasis

Radmila Micanovic, Brahmananda R. Chitteti, Pierre C. Dagher, Edward F. Srour, Shehnaz Khan, Takashi Hato, Allison Lyle, Yan Tong, Xue Ru Wu, Tarek M. El-Achkar

Research output: Contribution to journalArticle

14 Scopus citations


Tamm-Horsfall protein (THP) is a glycoprotein uniquely expressed in the kidney. We recently showed an important role for THP in mediating tubular cross-talk in the outer medulla and in suppressing neutrophil infiltration after kidney injury. However, it remains unclear whether THP has a broader role in neutrophil homeostasis. In this study, we show that THP deficiency in mice increases the number of neutrophils, not only in the kidney but also in the circulation and in the liver, through enhanced granulopoiesis in the bone marrow. Using multiplex ELISA, we identified IL-17 as a key granulopoietic cytokine specifically upregulated in the kidneys but not in the liver of THP-/- mice. Indeed, neutralization of IL-17 in THP-/-mice completely reversed the systemic neutrophilia. Furthermore, IL-23 was also elevated in THP-/-kidneys. We performed real-time PCR on laser microdissected tubular segments and FACS-sorted renal immune cells and identified the S3 proximal segments, but not renal macrophages, as a major source of increased IL-23 synthesis. In conclusion, we show that THP deficiency stimulates proximal epithelial activation of the IL-23/IL-17 axis and systemic neutrophilia. Our findings provide evidence that the kidney epithelium in the outer medulla can regulate granulopoiesis. When this novel function is added to its known role in erythropoiesis, the kidney emerges as an important regulator of the hematopoietic system.

Original languageEnglish (US)
Pages (from-to)2172-2182
Number of pages11
JournalJournal of the American Society of Nephrology
Issue number9
StatePublished - Sep 1 2015

ASJC Scopus subject areas

  • Nephrology

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